| Author | Message | ||
     Avc8130 |
Has anyone tried an R1 or R6 (pretty sure they are the same) master cylinder swap? They are radials made by Brembo and seem pretty popular on other sport bikes. ac | ||
| Garrett2 |
what benefit do you hope to gain by swapping to these master cylinders? | ||
| Barker |
I'm sure they are great for 2 calipers. I dunno about one. | ||
| Avc8130 |
"Feel" 2 calipers = 8 pistons Brick = 8 pistons There is SOME logic there LOL. ac | ||
| Barker |
yeah the first bit of travel in the ZTL2 is a BIT vague. (Message edited by barker on October 29, 2009) | ||
| Smoke4ndmears |
i'm curious about this as well. just about any 14mm would work no? | ||
| 1324 |
What are the piston diameters on the 1125 and the R1/6? How about the stock 1125 master cylinder? | ||
| Avc8130 |
R1/R6 are 16mm. ac | ||
| 1324 |
How about the caliper pistons? | ||
| Avc8130 |
Don't have them to measure. Preliminary research shows 2 27mm and 2 30mm pistons on each caliper. ac (Message edited by avc8130 on October 29, 2009) | ||
| Fmaxwell |
It's all about ratios. Saying 16mm and 14mm means nothing if you don't know the stroke the piston travels. If one lever has its pivot .5" from the piston and the other is 1" from the piston, the amount of fluid moved differs massively. The easiest way to tell: Measure how much fluid is pumped in one pull of the brake lever with the stock master cylinder and then measure how much is pumped in one pull with the R1/R6 master cylinder. If it's the same, you're good to go. If it's less with the R1/R6, don't even consider it. It will make the brakes far touchier -- if there's enough fluid moved to operate them. If the R1/R6 moves a little bit more, then you will have to squeeze harder to get the same amount of braking action. You could bolt an R1/R6 brake lever/master cylinder on and experiment -- really carefully. Try first with the bike not running. Then try while riding slow in a parking lot. You know the drill, I'm sure. I hope you're successful and I applaud your efforts. Radial brake master cylinders are supposed to work a lot better. What we really need is a linkage like you see on shocks to counteract the brake's non-linear response (i.e., twice the pressure seems produce far more than twice the stopping force). | ||
| 1324 |
You really need to know the diameters of the master cylinder and the caliper pistons so you can determine the two working areas. Since this is a hydraulic circuit, it's all about pressure. Easy to put in terms of a 'leverage ratio' by looking at caliper area to master cylinder area. Deviating from the stock ratio will have a significant impact on feel. Decreasing the ratio will yield less leverage; increasing, will provide more. In other words, the smaller the ratio, the more force needed at the brake lever to generate the same clamp force at the disc. The larger the ratio, the touchier the brakes become. Concerning stroke, a higher leverage ratio will mean the brake lever needs to move more to move the caliper pistons the same distance. But as mentioned, if you have a lower leverage ratio and it moves less, you need to apply more force at the lever to apply the same force at the disc. It's common practice to allow a lower leverage ratio when using a radial master cylinder to a certain degree due to the mechanism at work. You want to be close, though...and as mentioned, proceed slowly. I just did a quick search of the net for the piston diameters...no luck. Either I suck at the interweb or it really is hard to find. Might be worth a quick call to Customer service; they've surprised me in the past with technical knowledge. | ||
| Avc8130 |
What is the stock MC bore? 14mm? This is what is listed on the American Sportbike site. http://www.americansportbike.com/shoponline/ccp0-p rodshow/18001.html I was too lazy to walk outside and look. I know American Sportbike sells a 19mm radial nissin for use on ZTL2. http://www.americansportbike.com/shoponline/ccp0-p rodshow/16106-19.html The stock Yamaha radial is 16mm. ac | ||
| Fmaxwell |
It's not just piston diameters and area. It's about displacement -- the quantity of fluid moved when one pulls the lever, say, 1" That's what the lever ratio is all about. That's why brembo sells 16, 18, and 20 ratio levers. How far does the piston move when you pull the lever and, hence, how much fluid is pumped? | ||
| 1324 |
We're essentially discussing the same thing. I was tired when I wrote that last night, so I apologize if I wasn't completely clear. I agree that master cylinder depression length, which will determine flow, is important in creating proper system actuation. However, it is common practice to start with the m/c diameter and then figure out what depression length you need. Optimize the pressure and then tweak the length to get the proper flow to actuate the pistons enough. Brembo has that nice m/c with the adjustable lever ratio (distance from the pivot to the piston). Pricey, but nice since you can change the lever ratio without buying new hardware. | ||
| Jdugger |
I just bought the Brembo RSC19 (I think) with the adjustable leverage 18-20. I'll report back after this weekend on the track. | ||
| 1324 |
Great, please do. Aside from the spendy price tag, I've been eyeing this up for a while. It would be nice to fine tune at will. | ||
| Avc8130 |
For the price of that Brembo...I will live with no feel. $50 R6 master on Ebay is in the budget. | ||
| Avc8130 |
I THINK Jersey Thunder is running an R1 master on the street: http://www.badweatherbikers.com/buell/messages/290 431/502197.html ac | ||
| Carbonbigfoot |
Cheaper and easier to change pads, or just make sure the stockers are bedded in properly... R | ||
| Kevin_stevens |
Yes, I don't have any real issues with the brakes - I may after I take it to the track next month - but you can make a lot of changes a lot cheaper just playing with pads. I don't usually approach MC changes unless the overall pressure or travel is just wrong, which doesn't seem to be the case here. KeS | ||
| Vagelis46 |
Avc8130, just do it. A brembo 16mm will improve the ZTL2 for sure. I know people that have used a R1/R6 16mm brembo with ZTL, and they found improvement in the braking performance. So for the ZTL2 it will make more sense. Pads ?? I only use EBC GFA345HH-"Extreme" for my ZTL, since they are the only ones that can take the high temperatures developed on the single rotor. Pads are very important. | ||
| Jdugger |
> Cheaper and easier to change pads The big gains on the ZTL2 are using the right pads and fluids for the right application. For someone commuting, the stock pads are too aggressive. Downgrade. For a Novice-to-intermediate occasional track day rider, and "quick" street rider, the OEM pads are great. Upgrade to Motul RBF600 fluid and go on happy. For a faster track day rider, you need fluid and you need good race pads. When you start getting into Novice and Expert paces on braking oriented tracks, you need to start upgrading again. I'm running a mid-pack novice pace now, and the stock MC has some issues delivering the feel and pressures I'd like to have at the caliper. Hence, the MC upgrade. | ||
| Jdugger |
I got the Brembo RCS19 installed. It's pretty trick. Just riding around the driveway, I'd say it's a huge step up from the stock MC. The first half-to-inch of loose travel we are used to is gone. Brake comes on with one finger on the lever, and it's shockingly linear and progressive. Stoppies at 20MPH are like taking candy from a baby. It's a huge upgrade, I can tell already. Track report tomorrow night. I'm on the track all weekend this weekend and should get some good time to break it in and get a feel for it. I'm excited. | ||
| Dcmortalcoil |
Stock R1/R6 m/c are Nissin (correction - it's Brembo), takes the same brake switch. Not sure about needing a different brake line. I just bought one used. I've used Brembo 16mm m/c and found to be too soft (too touchy). Have RSC19 at 18mm leverage setting. Has a much better feel to it. Much firmer - needs to apply more force (but less travel). (Message edited by dcmortalcoil on November 03, 2009) | ||
| Avc8130 |
Stock R1/R6 are NOT Nissin. They are Brembo. There is a Brembo logo cast right into the master. Stock GSXR/Ninja are Nissin. ac |
